Discussion

The annual Perseid meteor shower peaks tonight, but sky conditions are iffy in the Mid-Atlantic region. The best time to look for the meteors is between around 11pm and 5am and there is a probably a 50/50 chance for favorable viewing conditions.

The Perseid meteor shower comes every August as the Earth passes through a cloud of dust that comes from Comet Swift-Tuttle as it approaches the sun. Earth's gravity pulls in some of the chunks of debris — small rocks comprised of iron-nickel, stone, other minerals or a combination of these — which turn into bright balls of hot gas when entering Earth's atmosphere. As darkness falls, the meteors appear to come from the constellation Perseus, hence the name; although late in the evening, the meteors originate higher in the sky than the constellation.

Perseid meteoroids hit our atmosphere at ~132,000 mph to produce the annual light show and this particular meteor shower is usually rich in “fireballs” because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus – about 26 kilometers in diameter whereas most other comets are much smaller with nuclei only a few kilometers across. As a result, Comet Swift-Tuttle produces a large number of meteoroids, many of which are large enough to produce fireballs. In fact, the Perseid meteor shower is considered the “fireball champion” of all of the annual meteor showers. Typically, the meteors are only the size of pebbles, some as small as a grain of sand. This is a good year for viewing with respect to the moon as there will be little interference from the currently waxing crescent moon. Jupiter, Venus and the crescent moon will align in the eastern sky just before sunrise, but whether sky conditions will permit a view of this is up in the air.